Document transport device

Abstract

To suppress a variation in an effect of a document pressing member pressing down documents.SOLUTION: A document transport device 120 includes: a paper feed tray 44 on which documents G are stacked; an ejection tray 43 provided below the paper feed tray 44; a transport mechanism 32 that transports the documents G from the paper feed tray 44 to the ejection tray 43 through a reading position (opening 40A); and a document holding member 21 provided on a lower surface of the paper feed tray 44, expands and contracts in a direction approaching and separating from the ejection tray 43, and presses down the documents G ejected to the ejection tray 43.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to a document conveying device that conveys a document to a reading position.

Background Art

[0002] In recent years, there has been an increasing demand for increasing the capacity of document conveying devices provided in document reading devices, and technologies for realizing increased capacity have been studied. For example, in Patent Document 1, documents stacked on a paper feed tray are sequentially fed one by one from the top to a conveyance path by a feeding unit, pass through an image reading position in the conveyance path, and are sequentially discharged from a discharge port onto a discharge tray provided directly below the paper feed tray in a stackable manner. In the document feeding device, there are provided a lifting means for lifting and lowering the paper feed tray, and a lifting control means for raising the paper feed tray in accordance with the feeding of the placed documents from the paper feed tray, and the discharge port is configured to move up and down by the same amount in accordance with the lifting and lowering of the paper feed tray.

[0003] However, in the above configuration, when a small amount of documents are placed on the paper feed tray, the drop between the discharge port and the discharge tray becomes large, and there is a problem that the documents are scattered on the discharge tray. Therefore, it is conceivable to improve the alignment of the documents by providing a document pressing member that presses the upper surface of the discharged documents (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described in Patent Document 1, when an output tray is provided below the paper feed tray, the document holder must be provided on the underside of the paper feed tray via a pivot point to accommodate changes in the amount of documents loaded on the output tray. When there are no documents in the output tray, or only a few documents on the output tray, the document holder hangs down and contacts the leading edge of the documents being ejected, causing them to fall onto the output tray and preventing them from flying too far. However, as the number of documents on the output tray increases, the tilt of the document holder increases. As a result, the point where the leading edge of the document contacts the document holder becomes further away from the output opening, reducing the consistency of the ejected documents.

[0006] Furthermore, as described in Patent Document 1, as the capacity of the document transport device increases, the maximum distance between the paper feed tray and the output tray increases. However, if the document holder is made longer, the tilt of the document holder increases when the paper feed tray is lowered or when a large number of documents are loaded onto the output tray, reducing the consistency of the output documents. Also, if the document holder is made longer, the force that holds the documents down becomes excessive when a large number of documents are loaded onto the output tray. On the other hand, if the document holder is shortened in order to reduce the tilt of the document holder, there is a risk that the documents will not come into contact with the document holder when the paper feed tray is raised and there are few documents on the output tray.

[0007] The present invention aims to provide a document transport device that can suppress variations in the effectiveness of the document holder member in holding down the document, taking the above circumstances into consideration. [Means for solving the problem]

[0008] To solve the above problems, the document transport device according to the present invention comprises a paper feed tray on which documents are loaded, an output tray provided below the paper feed tray, a transport mechanism for transporting the documents from the paper feed tray to the output tray via a reading position, and a document holder member provided on the lower surface of the paper feed tray, which extends and retracts in a direction approaching and moving away from the output tray, and holds down the documents that have been discharged into the output tray.

[0009] The document holder may include a holder portion provided on the lower surface of the paper feed tray, and a slide portion that is slidably held in the holder portion and pulled out from the holder portion by gravity.

[0010] The frictional resistance between the document holder and the document may be less than the frictional resistance between the documents themselves.

[0011] The document transport device may include a paper tray lifting mechanism that raises the paper tray as the amount of documents loaded in the paper tray decreases.

[0012] The document transport device may also include a discharge port lifting mechanism that raises and lowers a discharge port for discharging documents into the discharge tray according to the amount of documents loaded in the discharge tray. [Effects of the Invention]

[0013] According to the present invention, it is possible to suppress fluctuations in the effectiveness of the document holder in holding down the document. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic front view showing the internal configuration of an image forming apparatus according to one embodiment of the present invention. [Figure 2] This is a perspective view showing the external appearance of a document transport device according to one embodiment of the present invention. [Figure 3] This is a schematic front view showing the paper feeding mechanism and transport mechanism according to one embodiment of the present invention. [Figure 4] This is a schematic front view showing a transport mechanism and a paper feed tray lifting mechanism according to one embodiment of the present invention. [Figure 5] This is a schematic rear view showing the paper feed tray lifting mechanism and drive unit according to one embodiment of the present invention. [Figure 6] This is a schematic front view showing a transport mechanism and a paper feed tray lifting mechanism according to one embodiment of the present invention. [Figure 7]It is a front view showing a discharge port elevating mechanism according to an embodiment of the present invention. [Figure 8] It is a front view excluding the drive part from FIG. 7 according to an embodiment of the present invention. [Figure 9] It is a cross-sectional view of a guide part according to an embodiment of the present invention. [Figure 10] It is a front view showing a state where the guide part shown in FIG. 8 according to an embodiment of the present invention is raised. [Figure 11] It is a perspective view showing a document pressing member according to an embodiment of the present invention. [Figure 12] It is a perspective view showing a document pressing member according to an embodiment of the present invention. [Figure 13] It is a front view showing a document conveying device provided with a document pressing member according to an embodiment of the present invention. [Figure 14] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention. [Figure 15] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention. [Figure 16] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention. [Figure 17] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention. [Figure 18] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention. [Figure 19] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention. [Figure 20] It is a front view showing the operation of a document conveying device according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0015] Hereinafter, a document conveying device 120 and an image forming device 100 according to an embodiment of the present invention will be described with reference to the drawings.

[0016] First, the overall configuration of the image forming apparatus 100 will be described. Figure 1 is a schematic front view showing the internal configuration of the image forming apparatus 100. Hereafter, the front side of the page in Figure 1 will be considered the front side of the image forming apparatus 100, and the left and right directions will be described based on the direction in which the image forming apparatus 100 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr indicate top, bottom, left, right, front, and back, respectively.

[0017] The image forming apparatus 100 comprises a printer 1, a scanner 110, and a document transport device 120. The scanner 110 is located above the printer 1, and the document transport device 120 is located above the scanner 110. The document transport device 120 transports the document G via the reading position of the scanner 110. The scanner 110 is a flatbed image scanner that reads the document G and generates image data. The printer 1 forms an image on a sheet S based on the image data. In this embodiment, an example is shown in which the printer 1 forms an image using an electrophotographic method, but the printer 1 may also be configured to form an image using an inkjet method.

[0018] The printer 1 comprises a rectangular main housing 3. Inside the lower part of the main housing 3, there is a paper feed cassette 4 in which sheets S are stored, and a paper feed roller 5 that feeds the sheets S from the paper feed cassette 4 to the right. Above the paper feed cassette 4, there is an imaging device 6 that forms a toner image using an electrophotographic method, and above and to the right of the imaging device 6, there is a fixing device 7 that fixes the toner image onto the sheet S. Above the fixing device 7, there is an ejection roller 8 that ejects the sheet S with the toner image fixed on it, and an ejection tray 9 on which the ejected sheets S are stacked.

[0019] Inside the main housing 3, a transport path 10 is provided, which runs from the paper feed roller 5 through the image creation device 6 and the fixing device 7 to the discharge roller 8. The transport path 10 is mainly formed of plate-shaped members that face each other with gaps between them to allow the sheet S to pass through, and transport rollers 17 that grip and transport the sheet S are provided at multiple locations in the transport direction Y. Upstream of the image creation device 6 in the transport direction Y, a registration roller 18 is provided. To the right of the fixing device 7, a reversing transport path 10R is provided, which branches off from the transport path 10 downstream of the fixing device 7 in the transport direction Y and rejoins the transport path 10 upstream of the registration roller 18 in the transport direction Y.

[0020] The control unit 2 comprises an arithmetic unit and a memory unit (not shown). The arithmetic unit is, for example, a CPU (Central Processing Unit). The memory unit includes a storage medium such as ROM (Read Only Memory), RAM (Random Access Memory), or EEPROM (Electrically Erasable Programmable Read Only Memory). The arithmetic unit performs various processes by reading and executing the control program stored in the memory unit. Note that the control unit 2 may be implemented using only integrated circuits without the use of software.

[0021] A display and operation unit (not shown) is provided on the front of the scanner 110. The display and operation unit comprises a display panel, a touch panel superimposed on the display surface of the display panel, and a keypad adjacent to the display panel (not shown). The control unit 2 displays screens on the display panel that show the operation menus and status of the printer 1 and scanner 110, and controls each part of the printer 1 and scanner 110 in accordance with operations detected by the touch panel and keypad.

[0022] The basic image formation operation of printer 1 is as follows: When a single-sided print job is input to printer 1 from the display operation unit or an external computer, the paper feed roller 5 feeds the sheet S from the paper feed cassette 4 to the transport path 10, the registration roller 18, whose rotation has stopped, corrects the skew of the sheet S, and the registration roller 18 feeds the sheet S to the image formation device 6 at a predetermined timing. The image formation device 6 forms a toner image on the sheet S using an electrophotographic method. Subsequently, the fuser device 7 fixes the toner image to the sheet S by melting the toner image while holding and transporting the sheet S, and the discharge roller 8 discharges the sheet S into the discharge tray 9. In the case of double-sided printing, the sheet S with the toner image fixed on the first side is sent to the transport path 10 via the inversion transport path 10R, and the toner image is transferred to the second side.

[0023] [scanner] The scanner 110 comprises a first carriage 81 equipped with a light source and a reflector, a second carriage 82 equipped with two reflectors, a lens 83 for imaging light, an image sensor 84 for converting the imaged light into image data, and a contact glass 85 on which the original document G is placed.

[0024] The basic document scanning operation of the scanner 110 is as follows: When the user places a document G on the upper surface of the contact glass 85 and instructs the scanner 110 to scan, the first carriage 81 moves to the right at a speed V, and in conjunction with this, the second carriage 82 moves to the right at a speed V / 2. During this time, the light source illuminates the document G, and the reflected light from the document G is reflected by the reflector of the first carriage 81 and the reflector of the second carriage 82, guided to the lens 83, and formed on the image sensor 84 to be converted into an image signal. The image signal is output to the control unit 2 of the printer 1, where it is converted into image data.

[0025] [Document transport device] Next, the document transport device 120 will be described. Figure 2 is a perspective view showing the external appearance of the document transport device 120. Figure 3 is a schematic front view showing the paper feeding mechanism 31 and the transport mechanism 32. Figures 4 and 6 are schematic front views showing the transport mechanism 32 and the paper tray lifting mechanism 33. Figure 5 is a schematic rear view showing the paper tray lifting mechanism 33 and the drive unit 78. Of these, Figures 3, 4, and 5 show the paper tray 44 in its upper limit position, and Figure 6 shows the paper tray 44 in its lower limit position. Note that the document holder member 21 is omitted in Figures 3 to 6.

[0026] The document transport device 120 includes a paper feed tray 44 on which documents G are loaded, an output tray 43 located below the paper feed tray 44, a transport mechanism 32 that transports documents G from the paper feed tray 44 to the output tray 43 via a reading position (opening 40A), and a document holder member 21 located on the lower surface of the paper feed tray 44, which extends and retracts in a direction approaching and moving away from the output tray 43, and holds down documents G that have been discharged into the output tray 43.

[0027] The document transport device 120 (see Figure 2) has a generally rectangular bottom portion 40 formed in a flat shape, and a first wall portion 41 and a second wall portion 42 that face each other in the front-to-back direction (width direction intersecting the document transport direction Z of the document G). The rear edge of the bottom portion 40 is hinged to the rear of the contact glass 85 (see Figure 1) of the scanner 110. The bottom portion 40 also functions as a press plate that holds down the document G on the contact glass 85. The first wall portion 41 is provided from the left end to the center of the front edge of the bottom portion 40. The second wall portion 42 is provided over the entire rear edge of the bottom portion 40. The cover portion 46 covers the upper and left side of the space between the first wall portion 41 and the second wall portion 42. The lower left end of the cover portion 46 is hinged to the left end of the bottom portion 40.

[0028] [Paper tray] The paper feed tray 44 (see Figures 2 and 3) is located to the right of the center in the left-right direction of the document transport device 120, and in front of the second wall portion 42. The paper feed tray 44 is a plate-shaped member that is inclined so that the left side is lower. A pair of cursors 45 are provided on the upper surface of the paper feed tray 44 to align the front-to-back edges of the document G.

[0029] [Output tray] The output tray 43 is located below the paper feed tray 44. The output tray 43 is integrated with the bottom 40. The output tray 43 has a sloping surface in the center in the left-right direction, with the left side being lower. The left end of the output tray 43 has a wall 47 that contacts the left end of the output document G.

[0030] [Paper feeding mechanism] The paper feeding mechanism 31 (see Figure 3) is located in the space between the first wall portion 41 and the second wall portion 42. The paper feeding mechanism 31 includes a box-shaped holder 53 with an open bottom. Inside the holder 53, a feed roller 51, a driven roller 55, a drive roller 52, and an endless belt 56 are arranged with the front-to-back direction as the axial direction. The driven roller 55 is located to the left of the feed roller 51. The drive roller 52 is located to the left of the driven roller 55. The endless belt 56 is wrapped around the drive roller 52 and the driven roller 55. An auxiliary roller 57, with the front-to-back direction as the axial direction, is pressed against the lower surface of the lower portion of the endless belt 56.

[0031] The front and rear ends of the drive shaft 54 ​​of the drive roller 52 are supported by the first wall portion 41 and the second wall portion 42, and are connected to a drive unit (not shown) including a motor and reduction gear. The holder 53 is supported by the drive shaft 54 ​​and is pivotable about the drive shaft 54. The driving force of the drive shaft 54 ​​is transmitted to the feed roller 51 by a transmission mechanism (not shown) such as a gear train or an endless belt.

[0032] The sensor 58 detects when the paper tray 44 is positioned at a height that allows it to supply the original document G. The sensor 58 is a transmissive or reflective optical sensor and is located on the inner surface of the cover portion 46. A light-shielding plate 59 is provided on the upper part of the holder 53, protruding upward or to the side.

[0033] [Paper tray lifting mechanism] The paper feed tray lifting mechanism 33 (see Figures 4 and 5) is provided on the front of the first wall 41 and the rear of the second wall 42. The drive pulley 71 and driven pulley 72 (see Figure 5) are provided above and below the center of the rear of the second wall 42, respectively. The driven pulley 73 is provided at the height between the drive pulley 71 and the driven pulley 72, and to the left of the drive pulley 71 and the driven pulley 73. The guide pulley 76 is provided to the upper left of the driven pulley 72 and to the right of the driven pulley 73. The endless belt 70 is wound around the drive pulley 71, the driven pulleys 72 and 73, and the guide pulley 76. The drive unit 78 includes a motor 78M, a worm gear 78W, an idler gear 78i, and a drive gear 71G. The drive gear 71G is provided on the shaft of the drive pulley 71.

[0034] The driven pulleys 91, 92, 93 and the guide pulley 96 (see Figure 4) are located on the front surface of the first wall 41, facing the drive pulley 71, driven pulleys 72, 73, and guide pulley 76, respectively. The endless belt 90 is wrapped around the driven pulleys 91, 92, 93 and the guide pulley 96. The driven pulley 93 is mounted on a shaft common to the driven pulley 73.

[0035] The sliding portion 74 (see Figure 5) is provided at the left end of the rear edge of the paper feed tray 44. The second wall portion 42 is provided with a first slit 421 whose longitudinal direction is vertical. The first slit 421 is provided at a position corresponding to the left end of the rear edge of the paper feed tray 44. The sliding portion 74 passes through the first slit 421 and is coupled to the portion of the endless belt 70 between the drive pulley 71 and the driven pulley 72.

[0036] A lifting guide 75 is provided on the rear surface of the second wall portion 42. The lifting guide 75 is a rail-shaped member with its longitudinal direction in the vertical direction. The sliding portion 74 is slidable in the vertical direction along the lifting guide 75.

[0037] The sliding part 94 (see Figure 4) is located at the left end of the front edge of the paper feed tray 44. The sliding part 94 is coupled to the portion of the endless belt 90 between the driven pulley 91 and the driven pulley 92.

[0038] A lifting guide 95 is provided on the front surface of the first wall section 41. The lifting guide 95 is a rail-shaped member with its longitudinal direction in the vertical direction. The sliding section 94 is slidable in the vertical direction along the lifting guide 95.

[0039] The basic operation of the paper feed tray lifting mechanism 33 is as follows: The driving force generated by the motor 78M is transmitted to the drive gear 71G via the worm gear 78W and idler gear 78i. As the drive pulley 71 rotates together with the drive gear 71G, the endless belt 70 rotates, and consequently the driven pulleys 72 and 73 rotate. Also, as the driven pulley 93 rotates together with the driven pulley 73, the endless belt 90 rotates in sync with the endless belt 70. Since the paper feed tray 44 is connected to the endless belts 70 and 90 via sliding parts 74 and 94, the paper feed tray 44 moves up and down due to the forward and reverse rotation of the motor 78M.

[0040] The control unit 2 raises the paper feed tray 44 using the paper feed tray lifting mechanism 33. When the top surface of the document G loaded in the paper feed tray 44 is pressed against the feed roller 51, the holder 53 swings upward. When the holder 53 swings upward by a predetermined amount, the light shielding plate 59 blocks the light from the sensor 58. At this time, an appropriate load is applied between the top surface of the document G and the feed roller 51, enabling the feed roller 51 to feed out the document G. In other words, the control unit 2 controls the paper feed tray lifting mechanism 33 to raise the paper feed tray 44 as the amount of documents G loaded in the paper feed tray 44 decreases.

[0041] [Conveying mechanism] The transport mechanism 32 (see Figure 3) comprises a transport path 61 extending from the paper feeding mechanism 31 to the opening 40A, a plurality of transport rollers 62 arranged in the transport path 61, and a guide section 64 extending from the opening 40A to the discharge roller 69. The transport path 61 and the guide section 64 are mainly formed of plate-like members that face each other with a gap between them through which the original document G can pass. The opening 40A is a slit with its longitudinal direction in the front-to-back direction, provided in the area of ​​the bottom 40 that faces the first carriage 81 (see Figure 1) located in the home position. The opening 40A is an example of a reading position, which is the position where the scanner 110 reads the original document G. At the reading position, the plate-like member on the lower side of the transport path 61 is provided with an opening 61A corresponding to the opening 40A, and the lower surface of the original document G during transport is exposed downwards through the openings 40A and 61A.

[0042] The conveyor roller 62 comprises a drive roller 62D and a driven roller 62N (see Figure 3). A driven pulley 63N (see Figure 4) is provided on the shaft of the drive roller 62D. The drive pulley 63D is connected to a drive unit (not shown) which includes a motor and a reduction gear. The endless belt 60 is wrapped around the drive pulley 63D, the multiple driven pulleys 63N, and the guide pulley 63G. When the drive pulley 63D is driven, the rotation of the endless belt 60 causes the multiple driven pulleys 63N to rotate synchronously, and therefore the multiple conveyor rollers 62 also rotate synchronously.

[0043] [Discharge port lifting mechanism] Figure 7 is a front view showing the discharge port lifting mechanism 34. Figure 8 is a front view of Figure 7 with the drive unit 68 removed. Figure 9 is a cross-sectional view of the guide unit 64. Figure 10 is a front view showing the guide unit 64 shown in Figure 8 in the raised position.

[0044] [Guide Section] The guide section 64 (see Figures 7 to 10) is an integrated unit of a lower guide member 65 and an upper guide member 66 that are opposed to each other in the vertical direction. The lower guide member 65 (see Figure 9) comprises a generally rectangular plate-shaped portion 65P that forms the lower part of the transport path 61, and support portions 65S that support both the front and rear ends of the plate-shaped portion 65P. The upper guide member 66 comprises a generally rectangular plate-shaped portion 66P that forms the upper part of the transport path 61, and support portions 66S that support both the front and rear ends of the plate-shaped portion 66P. The left end of the front and rear support portions 66S of the upper guide member 66 is supported by the shaft (first pivot shaft 661) of the drive roller 62D of the transport roller 62 adjacent to the right side of the opening 40A. The guide section 64 is pivotable about the first pivot shaft 661.

[0045] A discharge roller 69 is provided at the right end of the guide section 64. The discharge roller 69 includes a drive roller 69D and a driven roller 69N positioned above the drive roller 69D. The drive roller 69D is supported at the right end of the support section 65S of the lower guide member 65, and the driven roller 69N is supported at the right end of the support section 66S of the upper guide member 66. The contact area between the drive roller 69D and the driven roller 69N is located at the downstream end of the guide section 64 in the transport direction Z, and serves as a discharge port 69A for discharging the document G from the guide section 64.

[0046] Cylindrical projections 65B are provided on the front and rear support portions 65S of the lower guide member 65 (see Figure 9). The projections 65B are formed, for example, by inserting a crimping pin into a through hole formed in the support portion 65S. The projections 65B are located away from the first pivot axis 661. In this embodiment, the projections 65B are provided to the right of the center in the left-right direction of the lower guide member 65. The projection 65B provided on the front support portion 65S protrudes forward, and the projection 65B provided on the rear support portion 65S protrudes rearward.

[0047] Connecting members 67 are provided at the front and rear of the lower guide member 65 (see Figures 7, 8, and 10). The front and rear connecting members 67 are supported by a second pivot shaft 672 located in the area of ​​the bottom 40 corresponding to the area below the guide portion 64, and the front and rear connecting members 67 can pivot together around the second pivot shaft 672. The second pivot shaft 672 is located to the left of the projection 65B, that is, in a position corresponding to the space between the first pivot shaft 661 and the projection 65B.

[0048] The connecting member 67 is provided with a groove 67U whose longitudinal direction is such that it moves away from and towards the second pivot shaft 672. The width of the groove 67U is slightly wider than the diameter of the projection 65B. The projection 65B is inserted into the groove 67U and is slidable along the groove 67U.

[0049] A drive unit 68 for driving the connecting member 67 is provided in the first wall portion 41 or the second wall portion 42 (in this embodiment, the first wall portion 41) (see Figure 7). The front connecting member 67 is provided with a driven gear 67N centered on the second pivot shaft 672. The drive unit 68 includes a motor 68M and a reduction gear train 68R. The reduction gear train 68R includes a worm gear 68W provided on the shaft of the motor 68M and one or more gears 68G that transmit driving force from the worm gear 68W to the driven gear 67N. When the motor 68M is driven, driving force is transmitted to the driven gear 67N via the reduction gear train 68R, and the front and rear connecting members 67 oscillate together.

[0050] For example, when the motor 68M is driven with the initial state shown in Figure 8, the connecting member 67 swings counterclockwise around the second pivot axis 672, as shown in Figure 10. As the connecting member 67 swings, the projection 65B slides along the groove 67U of the connecting member 67 in a direction away from the second pivot axis 672, causing the guide portion 64 to swing counterclockwise around the first pivot axis 661, and the discharge port 69A rises.

[0051] On the other hand, when the motor 68M is driven in the reverse direction, the connecting member 67 swings clockwise and the projection 65B slides toward the second pivot shaft 672, causing the guide part 64 to swing clockwise and the discharge port 69A to descend.

[0052] The document transport device 120 is equipped with a sensor (not shown) that measures the amount of documents G loaded in the output tray 43. The control unit 2 lowers the output port 69A to its lower limit position when the amount of documents G measured by the sensor is less than or equal to a predetermined amount. The control unit 2 raises the output port 69A as the measured amount of documents G increases. When some or all of the documents G loaded in the output tray 43 are removed, the control unit 2 lowers the output port 69A to a height corresponding to the measured amount of documents G. In other words, the control unit 2 controls the output port lifting mechanism 34 to raise and lower the output port 69A according to the amount of documents G loaded in the output tray 43.

[0053] [Document holder] Next, the configuration of the document holder member 21 will be described. Figures 11 and 12 are perspective views showing the document holder member 21. Figure 13 is a front view showing the document transport device 120 equipped with the document holder member 21.

[0054] The document holder member 21 includes a holder portion 22 provided on the lower surface of the paper feed tray 44, and a slide portion 23 that is slidably held in the holder portion 22 and pulled out from the holder portion 22 by gravity.

[0055] The holder portion 22 comprises a base plate portion 22B and a cover portion 22C. The base plate portion 22B is a generally rectangular plate-shaped member having a short side and a long side. An axis 24 is provided along one of the short sides of the base plate portion 22B (one end of the base plate portion 22B in the longitudinal direction). The base plate portion 22B is arranged such that the axis 24 is aligned in the front-rear direction. The axis 24 is supported by a support portion 44S provided on the lower surface of the paper feed tray 44.

[0056] The slide portion 23 is a roughly rectangular plate-shaped member that is smaller than the base portion 22B and has the same longitudinal direction as the base portion 22B. A groove 22G is provided on one side of the base portion 22B, along the longitudinal direction of the base portion 22B, and is sized to accommodate the slide portion 23. The groove 22G guides the sliding movement of the slide portion 23 in the longitudinal direction of the base portion 22B.

[0057] The cover portion 22C is provided on the base portion 22B so as to cover the slide portion 23 housed in the groove 22G. The cover portion 22C prevents the slide portion 23 from disengaging from the groove 22G. The groove 22G penetrates to the other end of the base portion 22B in the longitudinal direction. Therefore, the slide portion 23 can extend and retract from the other end of the base portion 22B. In other words, the document holder member 21 is expandable and retractable.

[0058] The tip of the slide portion 23, which extends and retracts from the other end of the substrate portion 22B, contacts the upper surface of the document G loaded in the output tray 43. When there is no document G in the output tray 43, the tip of the slide portion 23 contacts the upper surface of the output tray 43. The frictional resistance between the slide portion 23 and the document G is smaller than the frictional resistance between the documents G themselves. As a mechanism to reduce frictional resistance, for example, a roller (not shown) with the front-to-back direction as its axial direction may be provided at the tip of the slide portion 23. Alternatively, the tip of the slide portion 23 may be covered with a resin coating (not shown) such as polyester.

[0059] The support portion 44S, for example, has a concave shape that opens downward, housing the shaft 24 inside and supporting one or both ends of the shaft 24. The document holder member 21 can swing left and right around the shaft 24, but because one end of the base portion 22B is surrounded by the concave support portion 44S, the range of swingability of the document holder member 21 is limited. When only gravity acts on the document holder member 21, as shown in Figure 13, it maintains a posture that is slightly tilted counterclockwise with respect to the vertical.

[0060] When a document G discharged from the discharge port 69A comes into contact with the document holder member 21, the force with which the discharge roller 69 pushes the document G is not large enough to push the document holder member 21 away. Therefore, the posture of the document holder member 21 does not change, the leading edge of the document G descends along the left side of the document holder member 21, and passes through the space between the leading edge of the document holder member 21 and the top surface of the discharge tray 43. If a force greater than the force with which the discharge roller 69 pushes the document G acts on the document holder member 21, such as when a user removes a stacked document G, the document holder member 21 will retract in a counterclockwise direction without resistance to prevent damage.

[0061] Next, the operation of the document transport device 120 will be described. Figures 13 to 20 are front views showing the operation of the document transport device 120. The document transport device 120 may be equipped with various sensors (not shown) that detect the presence or absence of documents G in the paper feed tray 44 and the output tray 43, as well as the amount of documents loaded, and may be configured to control the paper feed tray lifting mechanism 33 and the output port lifting mechanism 34 according to the detection results of the sensors. However, in the following, the control contents of the paper feed tray lifting mechanism 33 and the output port lifting mechanism 34 will be limited to the basics, and the behavior of the document holder member 21 will be mainly described.

[0062] When power is turned on to the image forming apparatus 100 and the document transport device 120 and there are no documents G in the output tray 43, the control unit 2 lowers the paper feed tray 44 and the guide unit 64 to their lower limit positions (see Figure 13). In this case, the amount of documents G that can be loaded into the paper feed tray 44 is maximized. The tip of the sliding portion 23 of the document holder member 21 is in contact with the upper surface of the output tray 43 due to gravity. Also, since the sliding portion 23 is pushed as far as it can go into the holder portion 22, the length of the document holder member 21 is minimized.

[0063] Next, when a document G is loaded into the paper feed tray 44 and the operation to start scanning is performed on the display operation unit (not shown), the control unit 2 raises the paper feed tray 44 to a height where the top surface of the document G contacts the feed roller 51 (see Figure 14). At this time, the holder unit 22 rises while the slide unit 23 remains in place, so the slide unit 23 is pulled out relative to the holder unit 22, and the length of the document holder member 21 becomes longer compared to when the paper feed tray 44 is at its lowest position.

[0064] Next, the control unit 2 transports the document G using the paper feeding mechanism 31 and the transport mechanism 32 to be read by the scanner 110 and ejected into the ejection tray 43. When the document G is ejected, the leading edge of the document G first contacts the left side of the document holder member 21 (see Figure 15), but the posture of the document holder member 21 does not change, and the leading edge of the document G descends along the left side of the document holder member 21. When the document G reaches the lower end of the slide part 23 (see Figure 16), the document holder member 21 swings slightly counterclockwise, creating a gap between the slide part 23 and the ejection tray 43, and the leading edge of the document G passes through the gap to the right (see Figure 17). At this time, since the document G is held down by gravity acting on the document holder member 21, the document G flying out to the right is suppressed. Furthermore, because the top surface of the output tray 43 is sloped so that the left side is lower, the document G slides down to the left and comes into contact with the wall 47, where it stops (see Figure 18).

[0065] Similarly, subsequent copies of the original document G are ejected and loaded onto the ejection tray 43. Each time an original document G is ejected, the upper surface of the original document G on the ejection tray 43 rises, pushing up the slide section 23. However, the holder section 22 also rises by the same amount along with the paper feed tray 44, so the length of the document holder member 21 remains unchanged, and the inclination of the document holder member 21 also remains unchanged (see Figure 19). Here, the force with which the ejection roller 69 ejects the original document G is large enough to overcome the frictional resistance between the original documents G loaded on the ejection tray 43 and eject the original document G. On the other hand, the frictional resistance between the slide section 23 and the original document G is smaller than the frictional resistance between the original documents G themselves. Therefore, the slide section 23 does not hinder the ejection of the original document G by the ejection roller 69.

[0066] After all the documents G loaded in the paper feed tray 44 have been discharged into the output tray 43, and the documents G are removed from the output tray 43, the height of the paper feed tray 44 does not change, so gravity pulls the slide part 23 out from the holder part 22 and it comes into contact with the top surface of the output tray 43 (see Figure 20). At this time, the slide part 23 is pulled out to its maximum extent from the holder part 22, so the length of the document holder member 21 is at its maximum. The inclination of the document holder member 21 does not change.

[0067] The document transport device 120 according to the embodiment described above comprises a paper feed tray 44 on which documents G are loaded, an output tray 43 provided below the paper feed tray 44, a transport mechanism 32 that transports documents G from the paper feed tray 44 to the output tray 43 via a reading position (opening 40A), and a document holder member 21 provided on the lower surface of the paper feed tray 44, which extends and retracts in a direction approaching and moving away from the output tray 43, and holds down the documents G that have been discharged into the output tray 43. With this configuration, changes in the posture of the document holder member 21 are suppressed, so fluctuations in the effect of the document holder member 21 in holding down the documents G are suppressed, and the consistency of the loaded documents G can be improved.

[0068] Furthermore, according to the document transport device 120 of this embodiment, the document holder member 21 includes a holder portion 22 provided on the lower surface of the paper feed tray 44, and a slide portion 23 that is slidably held in the holder portion 22 and pulled out from the holder portion 22 by gravity. With this configuration, the document holder member 21 can be extended and retracted with a simple structure.

[0069] Furthermore, according to the document transport device 120 of this embodiment, the frictional resistance between the document holder member 21 and the document G is smaller than the coefficient of friction between the documents G themselves. With this configuration, the document holder member 21 does not obstruct the discharge of the documents G.

[0070] Furthermore, the document transport device 120 according to this embodiment includes a paper feed tray lifting mechanism 33 that raises the paper feed tray 44 as the amount of documents G loaded in the paper feed tray 44 decreases. This configuration allows for a larger capacity document transport device 120.

[0071] Furthermore, the document transport device 120 according to this embodiment includes an outlet lifting mechanism 34 that raises and lowers an outlet 69A for discharging documents G into the discharge tray 43 according to the amount of documents G loaded in the discharge tray 43. This configuration makes it possible to suppress a decrease in the consistency of documents G on the discharge tray 43.

[0072] The above embodiment may be modified as follows.

[0073] In addition to the configuration of the above embodiment, a biasing means (not shown) such as a spring that biases the slide portion 23 toward the discharge tray 43 may be provided in the holder portion 22. This configuration can improve the reliability of contact between the slide portion 23 and the original document G.

[0074] In addition to the configuration of the above embodiment, an actuator (not shown) may be provided that changes the amount of protrusion of the slide portion 23 from the holder portion 22 according to the distance between the lower surface of the paper feed tray 44 and the upper surface of the document G loaded in the output tray 43. With this configuration, the length of the document holder member 21 can be optimized according to the distance between the lower surface of the paper feed tray 44 and the upper surface of the document G loaded in the output tray 43. The distance between the lower surface of the paper feed tray 44 and the upper surface of the document G loaded in the output tray 43 may be calculated from the measurement results of a sensor (not shown) that measures the height of the paper feed tray 44 and a sensor (not shown) that measures the height of the upper surface of the document G loaded in the output tray 43, or it may be measured directly by a sensor (not shown) provided on the lower surface of the paper feed tray 44.

[0075] The document holder member 21 according to the above embodiment has a double structure comprising a holder portion 22 and a slide portion 23. However, it may also have a triple structure comprising a second slide portion (not shown) that is slidably supported by the slide portion 23 and pulled out from the slide portion 23 by gravity. With this configuration, the ratio of the minimum length to the maximum length of the document holder member 21 can be increased compared to the double structure, and the document transport device 120 can be made to accommodate further increases in capacity. Furthermore, by making the document holder member 21 a multi-layered structure of four or more layers, the ratio of the minimum length to the maximum length can be increased even further.

[0076] In addition to the configuration of the above embodiment, a biasing means (not shown) such as a spring that biases the document holder member 21 in a clockwise direction around the axis 24 may be provided on the support portion 44S. This configuration makes it possible to increase the certainty of contact between the slide portion 23 and the document G.

[0077] A document transport device 120 that does not have a paper feed tray lifting mechanism 33 may be provided with the document holding member 21 according to the above embodiment. Furthermore, a document transport device 120 that does not have an output port lifting mechanism 34 may be provided with the document holding member 21 according to the above embodiment. [Explanation of Symbols]

[0078] 21. Document holding member 22 Holder section 23 Slide section 32 Conveying mechanism 33. Paper feed tray lifting mechanism 34 Discharge port lifting mechanism 120 Document transport device

Claims

1. The paper tray on which the documents are loaded, A discharge tray is provided below the aforementioned paper feed tray, A transport mechanism that transports the aforementioned document from the paper feed tray, through the reading position, to the output tray. 、 A document holder member is provided on the lower surface of the paper feed tray, which extends and retracts in a direction that moves toward and away from the output tray, and holds down the document that has been discharged into the output tray. The system includes a paper feed tray lifting mechanism that raises the paper feed tray together with the document holder member as the amount of documents loaded in the paper feed tray decreases, The aforementioned document holder member is, A holder portion provided on the lower surface of the paper feed tray, A document transport device characterized by comprising a slide portion that is slidably held in the holder portion and pulled out from the holder portion by gravity.

2. The document transport device according to claim 1, characterized in that the frictional resistance between the document holder and the document is smaller than the frictional resistance between the documents themselves.

3. The document transport device according to claim 1 or 2, characterized in that it is equipped with a discharge port lifting mechanism that raises and lowers a discharge port for discharging the documents onto the discharge tray according to the amount of documents loaded onto the discharge tray.

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